Suspected mastermind of 9-11 attacks arrested in Pakistan.

Byline: Cam Simpson

WASHINGTON _ Pakistani agents arrested Khalid Shaikh Mohammed, the suspected mastermind behind the Sept. 11 terrorist attacks, during a bloodless, early morning raid Saturday in a city just outside Islamabad, U.S. and Pakistani officials said.

Although he is hardly a household name in the United States, intelligence and law enforcement authorities say Mohammed is likely the most dangerous al-Qaida operative in the world _ and perhaps the most important figure captured since the global manhunt for al-Qaida began after the worst terrorist attacks in U.S. history.

His 3 a.m. arrest with two other suspected extremists at a safehouse in the city of Rawalpindi, which is home to Pakistan's military headquarters, marks a huge victory for the United States in its war on terror, authorities said Saturday.

The precise fate of Mohammed, who had a $25 million FBI bounty on his head, was unclear, although officials believed he would soon be in U.S. custody. No matter where he goes, U.S. officials are expected to keep details about Mohammed's custody and whereabouts a closely guarded secret, as they have with other captured operatives.

The White House late Saturday commended Pakistan for its help, describing…